JP2009235545A - Metal oxide thin film formation device, and method for producing sheet with metal oxide thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production device for a sheet with a metal oxide thin film, which can uniformly form the sheet with a metal oxide thin film on the surface of a sheet at high speed in such a manner that the oxidizing degree in the thickness direction is made uniform, even in the case of a relatively thick oxide metal thin film of 50 to 300 nm, and to provide a method for producing the sheet with the metal oxide thin film. <P>SOLUTION: The production device for the sheet with the metal oxide thin film comprises: a conveying means which has a sheet guiding face 3 conveying a sheet while being brought into contact with the sheet 1 and conveying the sheet with the movement of the sheet guiding face; an evaporation source 8 scattering metal vapor 10 toward the sheet on the sheet guiding face; and an oxygen introduction means introducing oxygen for conducting oxidation reaction with the metal vapor, and wherein, a metal oxide thin film is continuously formed on the sheet to be conveyed. The oxygen introduction means comprises a plurality of introduction tubes arranged in the sheet width direction, further arranged on the upstream side and the downstream side in the sheet conveying direction 25 of an evaporation source 7, and are also projected toward a region between the evaporation source and the sheet guiding face. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metal oxide thin film forming apparatus and a method for producing a sheet with a metal oxide thin film.

  Conventionally, by depositing a thin film on a sheet exemplified by a plastic film, a metal vapor-deposited film serving as a material for a film capacitor, a magnetic recording tape, a packaging film or the like has been manufactured. For this production, for example, a roll-up type vapor deposition apparatus (for example, Non-Patent Document 1) is used in which a plastic film as a roll is unwound in a vacuum chamber, and is formed again after being formed into a thin film.

  The outline will be described with reference to FIG. FIG. 7A is a diagram showing components of a thin film forming apparatus that continuously forms a thin film on a sheet such as a plastic film. FIG. 7A shows only the main part, and the vacuum chamber and the intermediate roll for housing the structure are omitted. In FIG. 7 (a), a long sheet 1 is fed from an original fabric roll body 2, and an intermediate roller 4 is placed on a sheet guide surface 3 which is a surface of a cylindrical metal can that rotates along the traveling direction of the sheet. 5 is conveyed in a state of being wound from the winding point 33 to the peeling point 32 at a required winding angle determined by 5, and then wound around the intermediate roller 5 to form a winding roll body 6. Deposition in the crucible 7 (evaporation source) in the region between the film formation start point 30 and the film formation end point 31 restricted by the mask member 11 when the sheet 1 is conveyed onto the sheet guide surface 3. The vapor 10 evaporated from the material 8 adheres to the sheet 1, and a thin film 13 is formed on the sheet 1. The evaporation includes, for example, a method of heating the vapor deposition material using the principle of induction heating or resistance heating, and a method of heating the vapor deposition material by irradiating the vapor deposition material. The sheet guide surface 3 mainly has a role of conveying the sheet 1 without wrinkles and a role of efficiently releasing the heat load received by the sheet 1. For this reason, for example, it is controlled to a required temperature by temperature control by circulation of a known heat medium. In addition, not only a cylinder but also a method of conveying a sheet on a belt body can be seen.

  As a method of forming a metal oxide thin film using such a thin film forming apparatus, there is a method of forming a metal oxide thin film on a sheet by melting and evaporating a metal vapor deposition material and introducing oxygen in the middle thereof. Are known.

  For example, films with aluminum oxide or silicon oxide films have been proposed in the field of packaging films having excellent gas barrier properties as films with metal oxide films (for example, Patent Documents 1 and 2). In particular, in the vapor deposition of aluminum oxide, a method is generally used in which metal aluminum is heated and evaporated, and oxygen is introduced into the metal evaporation atmosphere to form an oxide film. In such a packaging film with a metal oxide film, a method of forming a metal oxide film of about 5 to 30 nm on a plastic film is proposed. Further, in the method of obtaining a metal oxide film of a material mainly composed of Co, CoNi, and Fe as a ferromagnetic material used for a magnetic recording material, in order to improve magnetic characteristics, a metal is partially applied in the film thickness direction. A method of oxidizing or obtaining a metalloid oxide is disclosed (for example, Patent Document 3). In this field, it is not used for the purpose of completely oxidizing a metal to obtain an insulating or transparent film. Further, a reinforcing film made of a metal material selected from metals, metalloids and alloys, and oxides and composites thereof is formed on one or both sides of a plastic film, and this is used as a support for a magnetic recording medium. It has been proposed (for example, Patent Documents 4 and 5).

  Thus, if the gas barrier property is aimed, a sufficient function can be exhibited at a film thickness of about 5 to 30 nm, and if the magnetic property of the magnetic recording material is aimed, it is in the film thickness direction of a thin film of 50 to 300 nm. Sufficient characteristics can be obtained by partial oxidation. However, when increasing the strength of the support as a reinforcing film for a support for magnetic recording media, it may be necessary to form a metal oxide thin film having a thickness of about 50 to 300 nm. In such a thin film, the metal is a thin film. Need to be uniformly oxidized in the thickness direction. Therefore, a method for forming a metal oxide with good oxidation reaction efficiency for oxidizing the entire thickness direction of the thin film is necessary.

  Conventionally, several techniques have been proposed as a method of introducing oxygen to form a metal oxide and oxygen introducing means used therefor. For example, in Patent Document 2, an oxygen nozzle is disposed at a position close to the sheet guide surface, and oxygen is introduced along the sheet conveyance direction. In this way, when the oxygen nozzle is disposed at a position close to the sheet guide surface, if a thin metal oxide thin film having a thickness of less than 50 nm is obtained, the thin film oxidized almost uniformly in the thickness direction of the thin film. However, when a relatively thick thin film of 50 nm or more is formed, the oxidation on the interface side with the sheet in the thickness direction of the thin film and / or the surface side of the thin film is more likely to proceed, and the degree of non-uniform oxidation in the thickness direction It is easy to become a film. Further, when the metal oxide thin film is formed at a sheet conveying speed of 100 m / min or more, there is a problem that the film thickness cannot be sufficiently increased.

  On the other hand, generally, when the speed is increased or the film thickness is increased, it is necessary to increase the amount of evaporated aluminum and the amount of oxygen introduced in proportion to the increase in the speed or film thickness. However, when a metal oxide thin film having a film thickness of 50 nm or more is to be formed at a transfer speed of 100 m / min or more as described above, the desired film thickness cannot be obtained unless the amount of aluminum evaporation is increased beyond the proportional amount. There was also. This is because, according to the knowledge of the inventors, the rate at which oxygen molecules introduced in the vicinity of the sheet guide surface collide with the metal vapor particles from the evaporation source increases, preventing the metal particles from reaching the sheet surface. It is estimated. Therefore, it is necessary to heat the metal material by applying a large electric power to the evaporation source. In addition, this leads to an increase in the temperature of the evaporation source, which increases the radiant heat from the evaporation source and sometimes causes the film to undergo thermal deformation (heat loss).

  In addition, Patent Document 6 discloses a technique in which an oxygen nozzle is disposed immediately above an evaporation source and oxygen is introduced in the same direction as the metal vapor from the evaporation source is directed to the sheet. In this oxygen nozzle, the oxygen nozzle is disposed at a position where the metal vapor from the evaporation source is larger, and oxygen is introduced in almost the same direction as the arrival of the metal vapor. It has a feature that the metal oxide thin film can be formed efficiently with little influence on the flight. However, since there is an oxygen nozzle directly above the evaporation source, metal particles adhere to the oxygen nozzle, and the attached metal falls to the evaporation source, causing a bumping phenomenon (splash) with the molten metal in the evaporation source and flying. There was a problem that coarse metal particles perforated the sheet or caused defects in the thin film.

In Patent Document 7, an oxygen gas nozzle is disposed in a metal vapor atmosphere evaporating from an evaporation source for the purpose of forming an optical multilayer film on a glass substrate rotating at a fixed place, and oxygen is directed upward. A technique for forming a metal oxide thin film having uniform film quality by introducing it is disclosed. However, when this oxygen introduction method is applied to a process of forming a thin film on a continuously conveyed sheet and a process of forming a film at an evaporation rate faster than Patent Document 6, the thickness of the thin film depends on the position of the oxygen nozzle. In some cases, the degree of oxidation was uneven in the direction.
JP 62-103359 A JP 2001-192808 A JP-A-62-275316 JP 2003-129229 A Japanese Patent Laid-Open No. 2007-226943 Japanese Patent Laid-Open No. 10-60626 JP-A-6-240440 Ken Ihouchi et al., “Polymer films and functional membranes”, Gihodo Publishing, April 1991, p. 198-203

  As described above, in the prior art, oxygen cannot be sufficiently supplied into the metal vapor, and it has been difficult to form a relatively thick metal oxide thin film of 50 to 300 nm on the sheet surface at high speed. Therefore, in view of the above-described problems of the prior art, the present inventors have prepared a metal oxide thin film-attached sheet manufacturing apparatus and metal capable of uniforming the oxidation degree in the thickness direction at high speed even with a particularly thick thin film. It was studied to provide a method for producing a sheet with an oxide thin film.

The present invention for achieving the above object is characterized by any one of the following configurations (1) to (14).
(1) A sheet guide surface that conveys the sheet while being in contact with the sheet, a conveying unit that conveys the sheet as the sheet guide surface moves, and a metal toward the sheet on the sheet guide surface A sheet with a metal oxide thin film, comprising: an evaporation source that scatters vapor; and an oxygen introduction means that introduces oxygen to cause an oxidation reaction with the metal vapor, and continuously forms a metal oxide thin film on the conveyed sheet The oxygen introduction means is configured by arranging a plurality of introduction pipes in the sheet width direction, and the oxygen introduction means are arranged upstream and downstream in the sheet conveyance direction of the evaporation source. An apparatus for producing a sheet with a metal oxide thin film, wherein the sheet is disposed and the introduction pipe projects toward a region between the evaporation source and the sheet guide surface.
(2) The shortest distance h between the evaporation source and the sheet guide surface is in the range of 200 to 800 [mm], and the opening of the introduction pipe is 0.2 × h [mm] or more from the evaporation source. And the metal oxide thin film-attached sheet manufacturing apparatus according to (1), wherein the apparatus is disposed at a distance of 0.8 × h [mm] or less.
(3) The length of the introduction pipe is 30 [mm] or more, and the inner cross-sectional area of the introduction pipe is in the range of 3 to 50 [mm ² ], (1) or (2) The manufacturing apparatus of the sheet | seat with a metal oxide thin film as described in).
(4) The metal oxide thin film forming apparatus according to any one of (1) to (3), wherein an opening of the introduction pipe faces the sheet guide surface.
(5) The metal oxide according to any one of (1) to (4), wherein the oxygen introduction unit has a mechanism for adjusting a distance of the opening from the evaporation source. Equipment for manufacturing sheet with physical thin film.
(6) The evaporation source is heated by an electron gun, and the evaporation source has a shape longer in the sheet width direction than the sheet conveyance direction, and further has a length in the sheet width direction of 300 [mm] or more. The apparatus for producing a sheet with a metal oxide thin film according to the above (5), characterized in that it exists.
(7) Using the apparatus according to any one of (1) to (6), in a reduced pressure atmosphere, metal vapor is allowed to fly from the evaporation source toward the sheet, and at the same time, oxygen is introduced into the metal vapor. A method of manufacturing a sheet with a metal oxide thin film that is introduced and continuously forms a metal oxide thin film on the sheet, the plurality of sheets being provided in the width direction of the sheet on the upstream side and the downstream side of the evaporation source A method for producing a sheet with a metal oxide thin film, characterized in that oxygen is introduced by projecting the introduction pipe of 1 to an area exposed to a metal vapor flow.
(8) The value obtained by dividing the oxygen introduction amount introduced from each introduction pipe of the oxygen introduction means by the inner cross-sectional area of the introduction pipe is in the range of 25 to 300 [× 10 ⁻⁶ m ³ / min / mm ² ]. The method for producing a sheet with a metal oxide thin film according to the above (7), wherein the sheet is controlled to be inside.
(9) The method for producing a sheet with a metal oxide thin film according to (7) or (8), wherein the metal vapor is aluminum vapor and an aluminum oxide film is formed on the sheet.
(10) The production rate of the sheet with a metal oxide thin film according to any one of (7) to (9), wherein a film formation rate of the metal oxide thin film is 400 [nm / second] or more. Method.
(11) Oxygen is introduced into a region in which the metal vapor is scattered and a virtual film formation rate in the metal vapor is 1500 [nm / second] or less. The manufacturing method of the sheet | seat with a metal oxide thin film in any one of 7)-(10).
(12) The production of a sheet with a metal oxide thin film according to any one of (7) to (11), wherein the thickness of the metal oxide thin film is in a range of 50 to 300 [nm]. Method.
(13) When the total light transmittance is T [%] and the film thickness of the metal oxide thin film is d [μm], the value of the optical density represented by the following formula is in the range of 1.0 to 20.0. It is a manufacturing method of the sheet | seat with a metal oxide film in any one of said (7)-(12) characterized by the above-mentioned.
(Optical density) =-{log (T / 100)} / d
(14) A method for producing a sheet with a double-sided metal oxide film, wherein a metal oxide thin film is formed on both sides of an electrically insulating sheet by the method described in any of (7) to (13) above.

  Here, as a typical sheet applied in the present invention, there are sheets such as a plastic film and paper. In particular, a plastic film is preferably used in the present invention. Examples of the material of the plastic film include polyolefins such as polyethylene and polypropylene, and polymer plastic films such as polyester, polycarbonate, polyimide, polyphenylene sulfide, aramid, and nylon. The plastic film may be a single layer or a laminate film having two or more layers.

  In the present invention, examples of the method for forming the metal oxide thin film include a vacuum deposition method and an ion plating method. Among these, the vacuum evaporation method is preferable because high-speed film formation with a film formation rate of several hundreds [nm / second] is possible. In the evaporation source of the vacuum evaporation method, as a method of heating the material, there are a resistance heating method and an electron beam heating method in addition to the induction heating method, and any of them can be applied. In particular, the electron beam heating method is the most suitable method for obtaining a uniform metal oxide thin film because the evaporation amount in the sheet width direction can be easily controlled so as to obtain a uniform film thickness distribution in the sheet width direction.

In the present invention, the “evaporation source” refers to a volume portion that melts a metal material that is a thin film material. A container for storing a metal material, a heat insulating material, a material supply device, a heater for heating, and the like are disposed around the evaporation source. A suitable one is appropriately selected depending on the method of heating the evaporation source. There is no particular limitation.
In the present invention, the “introducing pipe” refers to a pipe for introducing oxygen to a metal vapor atmosphere. In the present invention, the “opening pipe opening” refers to an outlet for sending oxygen from the “introducing pipe” toward the metal vapor atmosphere. This “introducing tube” preferably has a structure in which the cross-sectional shape of the surface perpendicular to the direction in which oxygen flows is the same and continues to the “opening tube opening”, and the cross-sectional shape is round, square, rectangular, etc. Either is acceptable. Further, in the present invention, the “length of the introduction pipe” refers to the length of the part where the introduction pipe forms a substantially straight line. In addition, when the introduction pipe is bent within a range of 45 [°] due to the influence of the arrangement space of the introduction pipe, the introduction pipe forms a straight line as described above. Means included in the part. The “inner cross-sectional area of the introduction pipe” refers to the area of the inner space where oxygen flows in a plane perpendicular to the direction in which oxygen flows.

  In the present invention, “upstream and downstream of the evaporation source” means a sheet connecting a center line in the sheet conveyance direction of the evaporation source and a center line in the conveyance direction of the sheet film formation area on the sheet guide surface. The upstream side in the sheet conveyance direction on the guide surface is defined as “upstream side of the evaporation source”, and the upstream side in the sheet conveyance direction on the sheet guide surface is defined as “downstream side of the evaporation source”. The “sheet deposition region” refers to a region of the sheet transported on the sheet guide surface that is ejected from the evaporation source and metal vapor is deposited on the sheet. In the case of a general wind-up type vapor deposition machine, it is called a mask between the sheet guide surface and the evaporation source so as to limit the area where the metal particles fly on the sheet surface and prevent the metal vapor from adhering to an extra place. An opening is provided. For simplicity, the “sheet deposition region” can also refer to the opening of the mask.

  In the present invention, the “metal vapor flow” refers to a flow of metal vapor flying from the evaporation source toward the sheet guide surface and the surrounding mask.

  In the present invention, the “film formation rate” refers to a speed at which the metal oxide is deposited on the surface of the sheet in the sheet film formation region, specifically, the sheet conveyance speed is v [m / sec], When the film thickness of the metal oxide thin film deposited on the sheet surface is d [nm] and the length of the sheet deposition region in the sheet conveyance direction is L [m], it indicates a value represented by the following formula. .

(Film formation rate) [nm / sec] = (v × d) / L (1)
In the present invention, the “virtual film formation rate in the metal vapor” refers to the amount per unit time that the metal vapor flies between the evaporation source and the sheet guide surface. Specifically, when the sheet is virtually arranged at a certain height from the evaporation source, it is the rate at which the metal oxide thin film is deposited on the sheet, and the unit is the same as the equation (1) [nm / Second].

  In the present invention, the “sheet guide surface” refers to a constituent element of a thin film forming apparatus that conveys a sheet while contacting a surface opposite to the thin film forming surface of the sheet when a thin film is formed on the sheet. This “sheet guide surface” mainly serves to convey the sheet without wrinkles and to efficiently release the heat received by the sheet. A typical one is a cylindrical one as shown in FIG. 1 described later, and conveys a sheet while rotating about an axis. In addition, not only the cylindrical shape but also a method of conveying a sheet on a belt body is known, but any one is effective in the present invention.

  In the present invention, the “region between the evaporation source and the sheet guide surface” refers to a region where a large amount of metal vapor is flying from the evaporation source, and the upward vertical direction from an arbitrary position of the metal melting portion of the evaporation source. Is an area within an angle of 45 ° and below the sheet guide surface.

  In the present invention, a metal material is evaporated and oxygen is introduced into the vapor atmosphere to provide a metal oxide thin film. The metal material is not particularly limited as long as the desired characteristics are obtained, but aluminum and A material mainly composed of copper is preferably used because it has a low melting point and is an inexpensive material. Aluminum oxide films and copper oxide films are preferably used because of their good characteristics such as gas barrier properties, rigidity, thermal expansion properties, and productivity. Examples of other materials include metals such as Zn, Sn, Ni, Ag, Co, Fe, Mn, Mg, In, and Ti. Among these materials, there are materials such as Sn, Mg, In, etc. in which oxides have semiconductor performance, or alloy materials thereof, but these are appropriately selected depending on the use of the sheet with a thin film, The application of the present invention is not limited.

  According to the present invention, as is clear from the comparison between Examples and Comparative Examples, which will be described later, even a relatively thick metal oxide thin film of 50 to 300 [nm] can be formed at high speed and in the thickness direction. A sheet with a metal oxide thin film having a metal oxide thin film having a substantially uniform oxidation degree can be produced.

  Hereinafter, an example in which the example of the best embodiment of the present invention is applied to a winding type vapor deposition apparatus will be described as an example with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of a wind-up type vapor deposition apparatus showing an embodiment of the production apparatus of the present invention, in which (a) shows only the main part, and a vacuum chamber and an intermediate roll for housing a structure are omitted. It is. Further, (b) is a schematic cross-sectional view in which the portion where the metal vapor of (a) is flying is enlarged and the positional relationship such as the arrangement of each component is easily explained. Further, FIG. 4 shows an overall schematic diagram illustrating the vacuum chamber and the vacuum pump, omitting details such as the oxygen nozzle, together with FIG. Note that components having the same or equivalent functions as those of the conventional example are denoted by the same reference numerals, and detailed description thereof is omitted.

  2 and 3 are schematic configuration diagrams of the apparatus viewed from the right hand of FIG. 2 and 3 show two examples in which the method of branching oxygen in the sheet width direction is changed. In FIG. 2, the introduction pipe 15 is branched from the tubular branch portion 18 arranged in the sheet width direction to each position in the sheet width direction. FIG. 3 shows an example of the branching portion 18 in which a branch path is provided in the tournament type so that the introduction path from the oxygen supply pipe 19 to each introduction pipe 15 has the same distance.

  The take-up type vapor deposition apparatus shown in FIG. 1 has a sheet guide surface 3 that conveys the sheet 1 while in contact with the sheet 1, and a cylindrical metal that conveys one sheet as the sheet guide surface 3 moves. Conveying means such as a can made, a crucible 7 (evaporation source) for scattering metal vapor toward the sheet 1 on the sheet guide surface 3, and an oxygen introduction means for introducing oxygen to cause an oxidation reaction with the metal vapor It has been. The oxygen introduction means is configured such that a plurality of introduction pipes 15 are arranged in the sheet width direction, and the plurality of introduction pipes 15 are arranged on the upstream side and the downstream side of the crucible 7 in the sheet conveyance direction. Further, each introduction pipe 15 protrudes toward a region between the crucible 7 and the sheet guide surface 3.

  In such an apparatus, the long sheet 1 is continuously fed out from the raw roll body 2 and is intermediate between the sheet guide surface 3 which is the surface of a cylindrical metal can that rotates along the traveling direction of the sheet. At a required winding angle determined by the rollers 4 and 5, the paper is conveyed in a state of being wound from the winding point 33 to the peeling point 32, and then wound around the intermediate roller 5 to form a winding roll 6.

In FIG. 4, the decompression chamber 41 is roughly divided into a winding chamber 41a for winding and unwinding a sheet and a film forming chamber 41b for performing vapor deposition, and a vacuum pump 42a for the winding chamber and a vacuum pump 42b for the film forming chamber, respectively. To reduce the pressure. The vacuum pump is often used in combination with a roughing pump and a high vacuum pump to reach a high vacuum. In normal vacuum vapor deposition, the pressure in the film forming chamber is reduced to 10 ⁻¹ [Pa] or less, and the vapor deposition is performed on the order of 10 ⁻³ to 10 ⁻² [Pa]. Generally, the winding chamber is also adjusted to a level of 10 ⁻² to 10 ⁰ [Pa] as long as the pressure in the film forming chamber is not affected.

  At this time, the metal vapor deposition material 8 in the crucible 7 is evaporated, and at the same time, a plurality of introduction pipes provided on the upstream side and the downstream side of the crucible 7 with respect to the sheet conveying direction are exposed to the region exposed to the metal vapor flow. Oxygen is introduced through the introduction pipe 15. Thereby, when the sheet 1 is conveyed onto the sheet guide surface 3, the vapor deposition material in the crucible 7 in the region between the film formation start point 30 and the film formation end point 31 limited by the mask member 11. The vapor 10 evaporated from 8 adheres onto the sheet 1, and a thin film 13 is formed on the sheet 1. The thin film 13 becomes a metal oxide by oxygen introduced into the metal vapor atmosphere 10 from the introduction pipe 15. That is, a metal oxide thin film 13 is formed on the surface of the sheet 1.

  Further, the formation of the metal oxide thin film will be described in detail with reference to FIG. 1B. When forming the thin film, the metal material 8 is put in the crucible 7 and heated by a heating method (not shown) to melt the metal material 8. State. When further heated, the metal vapor 10 begins to evaporate from the molten metal surface of the metal material 8. The vapor 10 of the metal thus vaporized flies toward the sheet 1 along the sheet guide surface 3. At this time, the presence of oxygen gas between the crucible 7 and the sheet guide surface 3 causes the metal vapor to undergo an oxidation reaction, and a metal oxide thin film 13 is formed on the sheet surface.

  As a method for melting and evaporating a metal, for example, there are a method of heating a vapor deposition material using the principle of induction heating or resistance heating, and a method of heating the vapor deposition material by irradiating the vapor deposition material. That is, a high-frequency induction heating method under reduced pressure, a resistance heating method, an electron beam method, a laser ablation method, and the like can be given. In order to increase the thickness of the metal oxide film, a high frequency induction heating method or an electron beam method is preferably used, and an electron beam method is preferably used if it is a high melting point material, for example, a melting point material of 1500 [° C.] or higher.

  Further, the sheet guide surface 3 mainly has a role of conveying the sheet 1 without wrinkles and a role of efficiently releasing the heat load received by the sheet 1. For this reason, for example, it is controlled to a required temperature by temperature control by circulation of a known heat medium. Specifically, it is cooled to, for example, about −20 [° C.] using a refrigerant such as ethylene glycol or silicone oil. In addition, a method of conveying a sheet on a belt body is also applicable, not limited to a cylinder.

  The major difference between this embodiment and the prior art described in FIG. 7A is that, in this embodiment, as shown in FIG. 1A, oxygen gas is applied to metal vapor. As the shape of the nozzle, a tubular one is selected, and as shown in FIG. 2, a plurality of introduction pipes 15 are arranged in the sheet width direction, and the introduction pipes 15 are connected to the crucible 7 serving as an evaporation source and the sheet guide surface. The crucible 7 is arranged on the upstream side and the downstream side in the sheet conveying direction so as to protrude toward the region between the two, that is, to protrude into the region exposed to the metal vapor flow flying from the crucible 7 to the sheet 1. Is a point.

  When the film thickness of the metal oxide thin film of 50 [nm] or more is formed at a sheet conveyance speed of 100 [m / min] or more, the metal vapor density from the evaporation source is relatively high. In order to react such a high vapor density metal vapor with oxygen and form a thin film having a uniform oxidation degree in the thickness direction of the thin film, it is necessary to introduce oxygen uniformly into the metal vapor region. For this purpose, it is necessary to bring the oxygen nozzle as close as possible to a region having a high metal vapor density. However, when a pinhole type nozzle having a plurality of pinholes, which has been widely used in the past, is brought close to a region where the metal vapor density is high, the volume of the nozzle body cannot be ignored, and as a result, the oxygen nozzle body is made of metal vapor. As a result, the flow is interrupted, and the efficiency of the metal adhesion amount actually adhered to the sheet surface with respect to the amount of vapor from the evaporation source is reduced. A typical example of this pinhole type nozzle is shown in FIG. Oxygen introduced in the direction of the arrow 17 from the oxygen supply pipe 19 is sent into a pinhole type nozzle having a plurality of pinholes on the side surface, and oxygen is released from each pinhole 21. There are also known a technique for changing the diameter of the pinhole at each position and a technique for changing the interval between the pinholes so that the same amount of oxygen is released from each pinhole as much as possible. However, the inventors, in a reduced-pressure atmosphere, supply oxygen with better directivity in the direction of the opening of the tubular member having an opening substantially at the end than such a pinhole type nozzle. I found out. Therefore, the present inventors, as a nozzle that does not block the flow of the metal vapor and allows oxygen to reach the inside of the metal vapor region, protrudes toward the region between the evaporation source and the sheet guide surface. We found that the introduction pipe was most suitable. Furthermore, in order to form a metal oxide thin film having a uniform oxidation degree in the thickness direction of the thin film, it is preferable to arrange the introduction pipes upstream and downstream in the sheet conveyance direction of the evaporation source, and in addition, in the sheet width direction. In order to obtain a metal oxide thin film having a uniform oxidation degree, it was concluded that it is preferable to arrange a plurality of introduction pipes in the sheet width direction.

  Further, in the vacuum deposition method, metal vapor comes from the evaporation source while diffusing upward. Therefore, the metal vapor density has a gradient distribution so that the vicinity of the evaporation source is the highest and the sheet surface to which the metal vapor adheres is the lowest. The inventors of the present invention have been able to introduce oxygen in a metal vapor having a gradient distribution in the height direction, and from an evaporation source of an introduction pipe suitable for forming a thin film having a uniform oxidation degree in the film thickness direction. The height of was examined. As a result, when the shortest distance h between the evaporation source and the sheet guide surface is in the range of 200 to 800 [mm], the opening of the introduction pipe is 0.2 × h [mm] or more from the evaporation source and is less than 0. It has been found that a height of 8 × h [mm] or less is suitable. When the introduction pipe is disposed at a position where the height from the evaporation source is lower than 0.2 × h [mm], the vapor density of the metal vapor is too large, so that oxygen does not sufficiently penetrate into the metal vapor, and the metal vapor Excess oxygen that is not used in the oxidation reaction tends to increase. As a result, the pressure in the film formation chamber becomes high and the evaporation of the metal vapor from the evaporation source becomes unstable, and the degree of oxidation in the thickness direction of the obtained metal oxide thin film depends on the interface side with the sheet and the thin film. There may be a problem that the thin film is uneven in the thickness direction, which becomes higher on the surface side and lower on the inner layer. On the other hand, when the introduction pipe is arranged at a position where the height from the evaporation source is higher than 0.8 × h [mm], the vapor density of the metal vapor becomes too small and oxygen collides with the metal vapor and reacts. As described above, excess oxygen that is not used for the oxidation of metal vapor increases, and the degree of oxidation in the thickness direction of the thin film easily changes depending on the direction of the introduction pipe, and the orientation of the introduction pipe is adjusted. In some cases, it becomes difficult.

  Furthermore, the present inventors have found that the metal vapor density optimum for introducing oxygen, the size of the evaporation source, the size of the film formation region of the sheet, the distance between the evaporation source and the sheet, the height from the evaporation source and the metal The relationship between the vapor density was derived and the appropriate height of the inlet pipe was determined. As a result, in the film formation conditions where the film formation rate of the metal oxide thin film is 400 [nm / second] or more, the virtual vapor is formed in the metal vapor in the region between the film formation region of the sheet and the evaporation source. It has been found that it is effective to arrange the opening of the introduction pipe in a region where the rate is 1500 [nm / sec] or less and introduce oxygen toward the metal vapor. When oxygen is introduced into a region where the virtual film formation rate in the metal vapor is higher than 1500 [nm / second] (that is, a position where the height from the evaporation source is low), the metal vapor density is large. May not penetrate and form a thin film having a non-uniform oxidation degree in the film thickness direction. More preferably, oxygen should be introduced into a region where the virtual film formation rate in the metal vapor is in the range of 1000 to 1500 [nm / second]. In the region where the virtual film formation rate in the metal vapor is smaller than 1000 [nm / second], the metal vapor density is relatively dilute, and the probability that the introduced oxygen reacts with the metal vapor is small and is not used for the oxidation reaction. Oxygen increases and the pressure in the film formation chamber may increase.

  In this embodiment, as a method for obtaining the virtual film formation rate in the metal vapor, a quartz-vibration type film thickness meter is placed on a straight line that has the shortest distance from the evaporation source in the film formation region of the sheet. It is possible to employ a method of arranging and directly measuring the virtual film formation rate in the metal vapor. Further, the virtual film formation rate in the metal vapor decreases as the height from the evaporation source increases.

  Further, as a method for obtaining the height y [m] from the evaporation source at which the virtual film formation rate in the metal vapor is 1500 [nm / sec] or less, the shortest distance from the evaporation source to the sheet guide surface is h [m]. When the height from the evaporation source for obtaining the “virtual film formation rate in metal vapor” is y [m], it can also be obtained by the following equation. That is, the opening of the introduction pipe may be arranged in a region that satisfies the relationship of the following formula.

y [m] ≧ (d × v × h) / (1500 × L) (2)
As for the horizontal position of the opening of the introduction pipe with respect to the evaporation source, the angle formed between the straight line forming the shortest distance between the opening of the introduction pipe and the evaporation source and the upward vertical direction from the evaporation source must be within 45 °. Is preferred. If it exceeds 45 °, oxygen will be introduced from a position far from the metal vapor flying into the film formation region of the sheet, and oxygen will not penetrate sufficiently into the metal vapor, resulting in a non-uniform oxide film in the film thickness direction. There is a possibility.

  Furthermore, in the apparatus of the present embodiment, the mechanism is capable of adjusting the distance from the evaporation source of the opening of the introduction pipe so that the opening of the oxygen introduction port can be arranged in the region of the optimum metal vapor density described above. It is preferable. For example, in FIG. 1, the introduction pipe 15 has a structure that can be easily detached from the branch portion 18, and the length of the deposition pipe 15 is different when the above-described film formation rate or the virtual film formation rate in the metal vapor is different. The configuration can be changed to a different introduction pipe.

In this embodiment, it is preferable that the introduction pipe used for supplying oxygen has a length of 30 [mm] or more. If it is shorter than 30 [mm], the introduction pipe cannot be arranged in the metal vapor having the optimum range of vapor density, or the arrangement of the introduction pipe is not allowed to protrude into the metal vapor. 2 and FIG. 3, members other than the introduction pipe 15 such as the branch portion 18 of the oxygen supply pipe as shown in FIG. 2 and FIG. 3 block the metal vapor 10, and the vapor deposition rate of 1 on the sheet may decrease. is there. Further, the introduction pipe preferably has an inner cross-sectional area of 3 to 50 [mm ² ]. If it is larger than 50 [mm ² ], the amount of the introduction pipe blocking the vapor flow increases, and the vapor deposition rate on the sheet may decrease. If it is smaller than 3 [mm ² ], oxygen diffuses in the atmosphere in the vicinity of the opening, and it may be difficult for oxygen to penetrate into the vapor stream. Furthermore, in this embodiment, the introduction pipe introduces oxygen with better directivity in the direction of the opening than the conventional pinhole type nozzle, and for this reason, the introduction pipe has a length. It is preferably 30 [mm] or more, and the inner cross-sectional area of the introduction tube is 3 to 50 [mm ² ].

  The introduction pipe has an opening at a substantial end in order to send out oxygen to a region where the metal vapor comes, and the opening is preferably directed to the sheet guide surface. By introducing oxygen toward the film to be formed, the ratio of the amount of oxygen leaking to the outside of the sheet and the metal vapor flow can be reduced, and a metal oxide thin film having a desired degree of oxidation can be obtained with a small amount of oxygen. . In addition, since the amount of oxygen that does not contribute to the oxidation reaction can be reduced, the pressure in the film formation chamber does not increase. The opening of the introduction pipe may be a cut made by cutting the introduction pipe, and the cut may be cut vertically or obliquely with respect to the axial direction of the pipe. However, if the opening area of the opening is extremely smaller than the inner cross-sectional area of the introduction pipe, oxygen diffuses into the atmosphere near the opening, and oxygen may not easily penetrate into the vapor stream. It is preferable that the inner cross-sectional shape of the introduction pipe is a structure that continues to the opening as it is.

  Further, it is preferable that an oxygen flow rate adjusting unit that independently adjusts the oxygen introduction amount of each of the oxygen introducing units disposed on the upstream side and the downstream side in the sheet conveyance direction of the evaporation source is provided. By this independent oxygen flow rate adjusting means, the distribution of the degree of oxidation in the thickness direction of the thin film can be adjusted more uniformly. Furthermore, it is preferable to include an oxygen flow rate adjusting means for independently adjusting the oxygen introduction amount of the plurality of introduction pipes arranged in the sheet width direction. With the independent oxygen flow rate adjusting means in the sheet width direction, the distribution of the degree of oxidation in the sheet width direction can be more uniformly controlled.

  In this embodiment, a vapor deposition machine that heats the evaporation source with an electron gun is more preferably applied. The evaporation source heated by the electron gun is the principle of heating and evaporating the metal by irradiating the electron gun to the molten metal, but by adjusting the irradiation time and input energy of the electron gun at each position in the sheet width direction Since the evaporation amount distribution in the sheet width direction can be changed relatively easily, a thin film having a more uniform degree of oxidation can be obtained in the sheet width direction when used in combination with the introduction tube.

  It is preferable that the evaporation source suitable for the present embodiment has a shape that is longer in the sheet width direction than the sheet conveyance direction, and the length in the sheet width direction is 300 mm or more. In this way, when the evaporation source is longer in the sheet width direction and the width for evaporating the metal becomes larger, the metal vapor is also evaporated from the adjacent region, especially in the central evaporation region. The oxygen tends to become difficult to penetrate into the metal vapor. Therefore, it is suitable as an object of this embodiment.

  Furthermore, the transmittance of the film with the metal oxide thin film is measured, and it is preferable to adjust and control the energy of the evaporation source and / or the amount of oxygen introduced so that the transmittance is substantially constant based on the transmittance. Measuring the transmittance in-line and maintaining it is preferable because the quality of transparency can be maintained. In addition, there is a method of adjusting the amount by the input energy (electric power) to the evaporation source, but it is easier and easier to adjust the oxygen introduction amount. However, when the quality of the thickness of the metal oxide thin film is important, it is preferable to control by the balance between the input power to the evaporation source and the amount of oxygen introduced. The transmittance monitored in-line may be the total light transmittance or the transmittance of light of a specific wavelength, but the light intensity is 500 to 600 which is strong due to the measurement accuracy and the resolution of the measuring equipment. It is preferable to substitute the transmittance of light having a specific wavelength of [nm].

In this embodiment, the value obtained by dividing the oxygen introduction amount introduced from each introduction pipe by the inner cross-sectional area of the introduction pipe is in the range of 25 to 300 [× 10 ⁻⁶ m ³ / min / mm ² ]. It is preferable to control so that it becomes. In addition, when oxygen is introduced by branching a plurality of introduction pipes from a single flow rate controller or the like, the range is 25 to 300 [× 10 ⁻⁶ m ³ / min / mm ² ]. It is preferable to select the number of introduction pipes in the sheet width direction. If it is larger than 300 [× 10 ⁻⁶ m ³ / min / mm ² ], the difference between the pressure inside the introduction pipe and the pressure outside the introduction pipe becomes large, and the oxygen gas exiting the opening of the introduction pipe diffuses. It may become easier and oxygen may not easily penetrate into the vapor. If the number of introduction pipes in the sheet width direction is selected so as to be smaller than 25 [× 10 ⁻⁶ m ³ / min / mm ² ], the number of introduction pipes in the sheet width direction increases and the steam flow is blocked. In some cases, the deposition rate of the thin film on the sheet is lowered.

  The present embodiment is particularly effective for a relatively thick film which is difficult to form a uniform oxidation degree in the film thickness direction. Specifically, a metal oxide thin film having a film thickness of 50 [nm] or more is used. More preferred for formation. On the other hand, when the film thickness is greater than 300 [nm], factors other than the oxidation reaction are the main factors in the uniformity in the thickness direction of the thin film, and thus the effect of the present embodiment is reduced and cannot be said to be a suitable target. Specifically, the difference in the angle at which the metal vapor enters and the speed at which the metal particles arrive in the film formation region of the sheet is the main factor of the film uniformity. Further, as a parameter of the rate at which the metal oxide thin film is deposited, a parameter called a dynamic rate [nm · m / min] obtained by multiplying the sheet conveyance speed [m / min] and the film thickness [nm] of the thin film is used. In the case of forming a metal oxide thin film having a thickness of 50 to 300 [nm], 10000 to 30000 [nm · m / min] is a film forming condition suitable for this embodiment at this dynamic rate.

  As a method of checking the degree of oxidation of the metal oxide thin film in the film thickness direction, a method of observing a section of the thin film cross section with a transmission electron microscope (TEM) is known. 5 and 6 are schematic diagrams showing the characteristics of the observation example. When observed with this method, for example, when a metal oxide thin film formed using a conventional pinhole type nozzle is observed from the upstream side and the downstream side in the sheet conveying direction in the vicinity of the sheet guide surface as shown in FIG. As shown in FIG. 5, on the interface side with the sheet and on the surface side of the thin film, a layer having a higher degree of oxidation than the center of the thin film is observed, and the entire thin film is observed as a three-layer structure. On the other hand, when the sheet with the metal oxide thin film produced according to the present embodiment is observed, the layer separation is observed as a substantially uniform layer as shown in FIG. Thus, the sheet in which the metal oxide thin film looks uniform is more effective in increasing the mechanical strength of the thin film, and is suitable for use as a reinforcing film used as a support for a magnetic tape.

In the present embodiment, when the metal oxide thin film is aluminum oxide, the surface resistance value of the thin film is preferably in the range of 10 ² to 10 ¹² [Ω / □]. The range of the surface resistance value is a region where the resistance value is likely to fluctuate even when the amount of oxygen introduced is relatively small, and surface resistance unevenness is likely to occur in the sheet width direction and the sheet conveyance direction. By applying, it becomes easy to adjust the surface resistance uniformly in the sheet width direction and the sheet conveying direction.

When the film thickness of the metal oxide thin film is d [μm] and the total light transmittance as a sheet including the metal oxide thin film is T [%], the value of the optical density represented by the following formula is 1. When it is in the range of 0 to 20.0, the optical density tends to fluctuate due to a small amount of oxygen change, and the metal particles that remain without being oxidized inside the thin film tend to be biased in the thickness direction. It is a condition suitable for application of the form.
(Optical density) =-{log (T / 100)} / d
Furthermore, by applying the oxygen introduction method of the present invention to metal oxide thin film formation on both sides of a sheet, a sheet having strength and dimensional stability that can be used for a base film for a magnetic tape, for example, can be obtained.

  The measurement method used in this example is shown below.

(1) Thickness of metal oxide thin film and cross-sectional structure of thin film Cross-sectional observation was performed under the following conditions, and the average value of the obtained thickness [nm] of 9 points in total was calculated, and the thickness of the metal oxide thin film [nm ].
Measuring apparatus: Transmission electron microscope (TEM) H-7100FA type Hitachi measurement conditions: Acceleration voltage 100 [kV]
Measurement magnification: 200,000 times Sample preparation: Observation surface of ultrathin film section method: TD-ZD cross-section measurement count: 3 points per field and 3 fields were measured.

(2) Surface resistance value Since the measurable device differs depending on the range of surface resistance value, first measure by the method of i), and measure the sample whose surface resistance value is too low to measure by the method of ii). did. The average value of the five measurement results was used as the surface resistance value in this embodiment.
i) High resistivity measurement Measured with the following measuring device in accordance with JIS-C2151 (1990).
Measuring device: Digital ultrahigh resistance / microammeter R8340 Advantest Co., Ltd. Applied voltage: 100 [V]
Application time: 10 seconds Measurement unit: Ω
Measurement environment: Temperature 23 ° C Humidity 65% RH
Number of measurements: Measure 5 times.
ii) Low resistivity measurement Measured using the following measuring device in accordance with JIS-K7194 (1994).
Measuring device: Lorester EP MCP-T360 Mitsubishi Chemical Measuring Environment: Temperature 23 ° C Humidity 65% RH
Number of measurements: Measure 5 times.

(3) Total light transmittance of sheet with thin film A sample was set in a “haze computer HZ-1” apparatus manufactured by Suga Test Instruments Co., Ltd., and the total light transmittance was measured. Five measurements were performed, and the average value was taken as the total light transmittance in this embodiment.

(4) Evaluation of composition in thickness direction of metal oxide film Composition analysis in the depth direction was performed under the following conditions. That is, the depth where the carbon concentration exceeds 50 [%] is taken as the interface between the metal oxide thin film layer and the polyester film, and each thickness position is excavated from the surface layer by 9 [nm] in terms of SiO _{2 under the following} ion etching conditions. The composition analysis is performed. Element information is obtained from the peak binding energy value, and the composition is quantified (at.%) Using the area ratio of each peak. Multiply the coefficient so that the distance from the surface obtained in terms of SiO ₂ to the interface is the thickness of the metal oxide thin film obtained in (1), and the horizontal axis represents the depth from the surface of the metal oxide thin film [ [nm] and the elemental composition ratio [%] on the vertical axis.

・ Measurement device: X-ray photoelectron spectrometer Quantera-SXM manufactured by PHI, USA ・ Excitation X-ray: monochromatic AlKα1,2 (1486.6 eV)
・ X-ray diameter: 100 [μm]
-Photoelectron escape angle: 45 °
・ Raster area: 2 × 2 [mm]
Ar ion etching: 2.0 [kV] 2.0 × 10 ⁻⁵ [Pa]
Sputtering speed: 3.68 nm / min (SiO ₂ equivalent value)
-Data processing: 9-point smoothing
(5) Measuring method of oxygen introduction amount Pipes to supply oxygen through the following mass flow controller to the introduction pipe for supplying oxygen into the metal vapor, adjust the flow rate of the mass flow controller, The flow rate display value was read when the optical monitor reached the desired transmittance.
-Mass flow controller: Advanced Energy Aera @ FC-7710CD
・ Calibration gas: Oxygen ・ Maximum flow rate: 40 [l / min]
[Example 1]
As a sheet, the winding type vacuum vapor deposition apparatus shown in FIG. 4 is used on one side of a polyethylene terephthalate film (“Lumirror” manufactured by Toray Industries, Inc.) having a thickness of 4.5 [μm] and a width of 1100 [mm]. Vapor deposition was performed under deposition conditions.

(Deposition conditions)
・ Evaporation source container: Alumina crucible ・ Evaporation source heating method: Heating with an electron gun ・ Evaporation material: Aluminum ・ Electron gun input power: 65 kW
・ Minimum distance between crucible of evaporation source and sheet guide surface: 450 [mm]
-Mask opening length in the film transport direction: 400 [mm]
-Mask opening length in the film width direction: 1000 [mm]
(Film transport conditions)
・ Conveying speed: 150 [m / min]
-Film width: 1100 [mm]
(Sheet guide surface conditions)
A cylindrical sheet guide surface was used as shown in FIG. Inside the sheet guide surface, a medium for adjusting the temperature of the surface of the sheet guide surface is circulated, and a medium having a constant temperature is introduced from a refrigerant circulation device outside the apparatus. Each condition is as follows.
-Diameter of cylindrical sheet guide surface: 1000 [mm]
・ Temperature of medium flowing inside the sheet guide surface: -20 [℃]
(Oxygen supply means conditions)
As shown in FIG. 4, the introduction pipe having a round cross section protruding toward the region between the evaporation source and the sheet guide surface was arranged under the following conditions.
Inner diameter of introduction pipe 15: 4 [mm] (inner cross-sectional area: about 12.6 [mm ² ])
・ Outer diameter of introduction pipe 15: 6 [mm]
-Length of the straight portion of the introduction pipe 15: 150 [mm]
・ Distance from crucible upper surface of evaporation source to opening of introduction pipe: 200 [mm]
・ Direction of introduction pipe 15: Direction in which the extended line of the straight part of introduction pipe 15 having an opening is the lowest point of the sheet guide surface ・ Number of introduction pipes in sheet width direction: 10 ・ Introduction pipes in sheet width direction Interval: 105 [mm] equally spaced (the interval between the introduction pipes at both ends is 945 [mm])
(Formation of metal oxide thin film)
The undeposited film roll is set on the raw roll body 2 in FIG. 4, the film is placed along the intermediate roller 4, the sheet guide surface 3, and the intermediate roller 5, and the film end is attached to the winding roll body 6. did. In the apparatus, an alumina crucible 7 having a volume portion of 150 [mm] in the sheet conveying direction and 1500 [mm] in the sheet width direction is arranged so that the longitudinal direction of the crucible 7 is the same as the film width direction, 20 [kg] of aluminum was set as the metal material 8 to this. Then, the winding chamber 41a and the film forming chamber 41b of the vapor deposition machine were depressurized, and the vacuum pressure in the film forming chamber 41b was exhausted to 5 × 10 ⁻³ [Pa]. Thereafter, the aluminum in the crucible 7 was melted by the electron gun heating method with the shutter member 51 closed. The electric power input was 75 [kW]. After confirming that all of the aluminum material was melted, the electric energy of the electron gun was finely adjusted to about 60 [kW]. The tension of the raw roll body 2 is set to 110 [N], the tension of the take-up roll body 6 is set to 140 [N], and the speed of the sheet guide surface 3 and the intermediate rollers 4 and 5 is set to 150 [m / min]. The conveyance of the film was started at a speed. Thereafter, aluminum was deposited with the shutter member 51 opened. The optical monitor 52 was used to monitor whether the aluminum film was uniformly deposited in the width direction, and the power distribution of the electron gun to the crucible was finely adjusted so that the transmittance was constant. Here, the transmittance is a transmittance measured through a filter having a central wavelength of 565 [nm] using a halogen lamp as a light source. There are 11 optical monitors 52 in the film width direction, and the 11 transmittances were adjusted to 0.05%. The value of transmittance of 0.05% is a guideline for the film thickness of 60 [nm] of the metal aluminum thin film. In this state, the pressure of the vacuum gauge 10 was 2.0 × 10 ⁻² [Pa]. Thereafter, the amount of oxygen introduced was increased to 25 [l / min] from the introduction pipe 15 on the unwinding side and the winding side in the sheet conveying direction of the crucible 7. As the oxygen was introduced, the pressure in the film forming chamber 41b became 3.5 × 10 ⁻² [Pa]. In this state, when the film was observed from the monitoring window 53 on the winding side, the film was brownish and transparent. The transmittance was 30% as an average value of 11 optical monitors. In this state, 11000 m of film was wound and conveyed to form a film with an aluminum oxide film. Thereafter, the shutter member 51 was closed to stop the introduction of oxygen, and the power supply to the electron gun for heating the evaporation source was cut off. And the conveyance speed was lowered to 5 [m / min], and the pressure release of the winding chamber 41a and the film-forming chamber 41b was performed.

The thickness of the aluminum oxide film thus formed was in the range of 100 ± 10 [nm] as a result of TEM cross-sectional observation. The total light transmittance of the deposited film taken out after the film formation was 53%. The surface resistance value was 1.5 × 10 ⁵ [Ω / □]. The composition analysis result in the thickness direction of the aluminum oxide film of this deposited film is shown in FIG. 11, and aluminum and oxygen were almost uniformly distributed in the film thickness direction. Table 1 summarizes the deposition conditions and evaluation results of the metal oxide thin film.

[Example 2]
A metal oxide thin film was formed in the same manner as in Example 1 except that the following points were changed.

(Deposition conditions)
・ Evaporation source container: Alumina crucible ・ Evaporation source heating method: Heating with an electron gun ・ Evaporation material: Aluminum ・ Electron gun input power: 65 kW
・ Minimum distance between crucible of evaporation source and sheet guide surface: 600 [mm]
-Opening length in the direction of film conveyance: 600 [mm]
-Mask opening length in the film width direction: 1000 [mm]
(Oxygen nozzle condition)
As shown in FIG. 4, the round tubular oxygen inlet was disposed under the following conditions.
Inner diameter of introduction pipe 15: 4 [mm] (inner cross-sectional area: about 12.6 [mm ² ])
・ Outer diameter of introduction pipe 15: 6 [mm]
-Length of the straight portion of the introduction pipe 15: 150 [mm]
・ Distance from crucible upper surface of evaporation source to opening of introduction pipe: 200 [mm]
・ Direction of introduction pipe 15: Direction in which the extended line of the straight part of introduction pipe 15 having an opening is the lowest point of the sheet guide surface ・ Number of introduction pipes in sheet width direction: 10 ・ Introduction pipes in sheet width direction Interval: 105 [mm] equally spaced (the interval between the introduction pipes at both ends is 945 [mm])
(Formation of metal oxide thin film)
An undeposited film roll is set on the original roll body 2 in FIG. 4, the film is placed along the intermediate roller 4, the sheet guide surface 3, and the intermediate roller 5, and the film end is attached to the winding roll body 6. . In the apparatus, an alumina crucible 7 having a volume of 150 [mm] in the sheet conveying direction and 1500 [mm] in the sheet width direction is arranged so that the longitudinal direction of the crucible is the same as the film width direction. 20 [kg] of aluminum was set as the metal material 8. Then, the winding chamber 41a and the film forming chamber 41b of the vapor deposition machine were depressurized, and the vacuum pressure in the film forming chamber 41b was exhausted to 5 × 10 ⁻³ [Pa]. Thereafter, the aluminum in the crucible 7 was melted by the electron gun heating method with the shutter member 51 closed. The electric power input was 75 [kW]. After confirming that all of the aluminum material was melted, the electric energy of the electron gun was finely adjusted to about 60 [kW]. The tension of the raw roll body 2 is set to 110 [N], the tension of the take-up roll body 6 is set to 140 [N], and the speed of the sheet guide surface 3 and the intermediate rollers 4 and 5 is set to 150 [m / min]. The conveyance of the film was started at a speed. Thereafter, aluminum was deposited with the shutter member 51 opened. Whether the aluminum film was uniformly deposited in the width direction was monitored by the optical monitor 52, and the power distribution of the electron gun to the crucible 7 was finely adjusted so that the transmittance was constant. There are 11 optical monitors 52 in the film width direction, and the 11 transmittances are adjusted to 0.05%. The value of transmittance of 0.05% is a guideline for the film thickness of 60 [nm] of the metal aluminum thin film. In this state, the pressure of the vacuum gauge 10 was 2.0 × 10 ⁻² [Pa]. Thereafter, the oxygen introduction amount was increased to 30 [l / min] from the upstream side and downstream side introduction pipes 15 in the sheet conveying direction of the crucible. As oxygen was introduced, the pressure in the film formation chamber 41b became 3.0 × 10 ⁻² [Pa]. In this state, when the film was observed from the monitoring window 53 on the winding side, the film was brownish and transparent. The transmittance was 30% as an average value of 11 optical monitors 52. In this state, 11000 [m] of film was wound and conveyed to form a film with an aluminum oxide film. Thereafter, the shutter member 51 was closed to stop the introduction of oxygen, and the power supply to the electron gun for heating the evaporation source was cut off. And the conveyance speed was lowered to 5 [m / min], and the pressure release of the winding chamber 41a and the film-forming chamber 41b was performed.

The thickness of the aluminum oxide film thus formed was in the range of 100 ± 10 [nm] as a result of TEM cross-sectional observation. The total light transmittance of the deposited film taken out after the film formation was 53%. The surface resistance value was 2.7 × 10 ⁵ [Ω / □]. Table 1 summarizes the deposition conditions and evaluation results of the metal oxide thin film.

[Comparative Example 1]
As an electrical insulating sheet, on one side of a polyethylene terephthalate film (“Lumirror” manufactured by Toray Industries, Inc.) having a thickness of 4.5 [μm] and a width of 1100 [mm], a winding type vacuum vapor deposition apparatus shown in FIG. Vapor deposition was performed under the following vapor deposition conditions.
(Deposition conditions)
・ Evaporation source container: Alumina crucible ・ Evaporation source heating method: Heating with an electron gun ・ Evaporation material: Aluminum ・ Electron gun input power: 75 kW
・ Minimum distance between crucible of evaporation source and sheet guide surface: 450 [mm]
-Mask opening length in the film transport direction: 400 [mm]
-Mask opening length in the film width direction: 1000 [mm]
(Film transport conditions)
・ Conveying speed: 150 [m / min]
-Film width: 1100 [mm]
(Sheet guide surface conditions)
A cylindrical sheet guide surface 3 was used as shown in FIG. Inside the sheet guide surface 3, a medium for adjusting the temperature of the surface of the sheet guide surface is circulated, and a medium having a constant temperature is introduced from a refrigerant circulation device outside the apparatus. Each condition is as follows.
-Diameter of cylindrical sheet guide surface: 1000 [mm]
・ Temperature of medium flowing inside the sheet guide surface: -20 [℃]
(Oxygen supply means)
A pinhole type nozzle as shown in FIG. 8 was arranged under the following conditions.
-Inner diameter of pinhole type nozzle 20: 14 [mm], outer diameter: 18 [mm]
-Diameter of pinhole 21: 1 [mm]
・ Pitch of pinhole 21 array: 15 [mm]
-Distance from the top surface of the metal material 8 of the evaporation source to the pinhole: 400 [mm]
-Direction of pinhole 21: Direction in which the extension line of pinhole 21 is the lowest point of sheet guide surface 3 (formation of metal oxide thin film)
An undeposited film roll is set on the original fabric roll body 2 in FIG. 9, the film 1 is placed along the intermediate roller 4, the sheet guide surface 3, and the intermediate roller 5, and the film end is attached to the winding roll body 6. did. In the apparatus, an alumina crucible 7 having a volume of 150 [mm] in the sheet conveying direction and 1500 [mm] in the sheet width direction is arranged so that the longitudinal direction of the crucible is the same as the film width direction. 20 [kg] of aluminum was set as the metal material 8. Then, the winding chamber 41a and the film forming chamber 41b of the vapor deposition machine were depressurized, and the vacuum pressure in the film forming chamber 41b was exhausted to 5 × 10 ⁻³ [Pa]. Thereafter, the aluminum 8 in the crucible 7 was melted by the electron gun heating method with the shutter member 51 closed. The electric power input was 75 [kW]. After confirming that all of the aluminum material was melted, the electric energy of the electron gun was finely adjusted to about 60 [kW]. The tension of the raw roll body 2 is set to 110 [N], the tension of the take-up roll body 6 is set to 140 [N], and the speed of the sheet guide surface 3 and the intermediate rollers 4 and 5 is set to 150 [m / min]. The conveyance of the film was started at a speed. Thereafter, aluminum was deposited with the shutter member 51 opened. Whether the aluminum film was uniformly deposited in the width direction was monitored by the optical monitor 52, and the power distribution of the electron gun to the crucible 7 was finely adjusted so that the transmittance was constant. There are 11 optical monitors 52 in the film width direction, and the 11 transmittances were adjusted to 0.05%. Note that the transmittance of 0.05% is a guideline for the thickness of the metal aluminum thin film of 60 [nm]. In this state, the pressure of the vacuum gauge 10 was 2.0 × 10 ⁻² [Pa]. Thereafter, the oxygen introduction amount was increased from the upstream and downstream pinhole type nozzles 20 in the sheet conveying direction of the crucible 7 and introduced up to 32 [l / min]. The pressure in the film forming chamber 41b was 3.2 × 10 ⁻² [Pa] according to the introduction of oxygen. In this state, when the film was observed from the monitoring window 53 on the winding side, the film was brownish and transparent. The transmittance was 30% as an average value of 11 optical monitors 52. In this state, 11000 [m] of film was wound and conveyed to form a film with an aluminum oxide film. Thereafter, the shutter member 51 was closed to stop the introduction of oxygen, and the power supply to the electron gun for heating the evaporation source was cut off. And the conveyance speed was lowered to 5 [m / min], and the pressure release of the winding chamber 41a and the film-forming chamber 41b was performed. The thickness of the aluminum oxide film thus formed was 45 [nm] ± 10 nm as a result of TEM cross-sectional observation. The total light transmittance of the deposited film taken out after the film formation was 63%. The composition analysis result in the thickness direction of the aluminum oxide film of this deposited film is shown in FIG. 12, and it was a distribution in which the amount of aluminum was relatively larger in the central portion than in the vicinity of the surface in the film thickness direction or near the interface. The surface resistance value was 4.2 × 10 ⁸ [Ω / □]. Table 1 summarizes the deposition conditions and evaluation results of the metal oxide thin film.

[Comparative Example 2]
As an electrical insulating sheet, on one side of a polyethylene terephthalate film (“Lumirror” manufactured by Toray Industries, Inc.) having a thickness of 4.5 [μm] and a width of 1100 [mm], a winding type vacuum vapor deposition apparatus shown in FIG. Vapor deposition was performed under the following vapor deposition conditions. The difference from the apparatus (FIG. 9) in Comparative Example 1 is that the position of the pinhole type nozzle 20 is brought closer to the crucible 7.
(Deposition conditions)
・ Evaporation source container: Alumina crucible ・ Evaporation source heating method: Heating with an electron gun ・ Evaporation material: Aluminum ・ Electron gun input power: 75 kW
・ Minimum distance between crucible of evaporation source and sheet guide surface: 450 [mm]
-Mask opening length in the film transport direction: 600 [mm]
-Mask opening length in the film width direction: 1000 [mm]
(Oxygen supply means conditions)
Pinhole array nozzles as shown in FIG. 8 were arranged under the following conditions.
-Inner diameter of pinhole type nozzle 20: 14 [mm], outer diameter: 18 [mm]
-Diameter of pinhole 21: 1 [mm]
・ Pitch of pinhole 21 array: 15 [mm]
-Distance from the upper surface of the evaporation material 8 to the pinhole 21: 200 [mm]
The direction of the pinhole type nozzle 20: the direction in which the extended line of the pinhole 21 is the lowest point of the sheet guide surface 3 (formation of a metal oxide thin film)
An undeposited film roll is set on the original fabric roll body 2 in FIG. 10, the film 1 is placed along the intermediate roller 4, the sheet guide surface 3, and the intermediate roller 5, and the film end is attached to the winding roll body 6. did. In the apparatus, an alumina crucible 7 having a volume of 150 [mm] in the sheet conveying direction and 1500 [mm] in the sheet width direction is arranged so that the longitudinal direction of the crucible 7 is the same as the film width direction. 20 [kg] of aluminum was set as the metal material 8. Then, the winding chamber 41a and the film forming chamber 41b of the vapor deposition machine were depressurized, and the vacuum pressure in the film forming chamber 41b was exhausted to 5 × 10 ⁻³ [Pa]. Thereafter, the aluminum 8 in the crucible 7 was melted by the electron gun heating method with the shutter member 51 closed. The electric power input was 75 [kW]. After confirming that all the aluminum material 8 was melted, the electric energy of the electron gun was finely adjusted to about 60 [kW]. The tension of the unwinding roll body 2 is set to 110 [N], the tension of the winding roll body 6 is set to 140 [N], and the speed of the sheet guide surface 3 and the guide rollers 4 and 5 is set to 150 [m / min]. The conveyance of the film was started at a speed. Thereafter, aluminum was deposited with the shutter member 51 opened. The optical monitor 52 was used to monitor whether the aluminum film was uniformly deposited in the width direction, and the power distribution of the electron gun to the evaporation source was finely adjusted so that the transmittance was constant. There are 11 optical monitors 52 in the film width direction, and the 11 transmittances were adjusted to 0.05%. Note that the transmittance of 0.05% is a guideline for the thickness of the metal aluminum thin film of 60 [nm]. In this state, the pressure in the film forming chamber 41b was 2.0 × 10 ⁻² [Pa]. Thereafter, the oxygen introduction amount was introduced from the upstream and downstream pinhole type nozzles 20 in the sheet conveyance direction of the evaporation source in an amount of 20 [l / min], but the pressure in the film formation chamber 41b was changed according to the oxygen introduction. Since it gradually increased and exceeded 1.0 × 10 ⁻¹ [Pa], the introduction of oxygen was once stopped. Thereafter, the sheet conveyance speed was lowered to 80 [m / min], and the input power distribution of the electron gun was finely adjusted so that the transmittance of the 11 optical monitors 52 in the film width direction was again 0.05%. In this state, the pressure in the film forming chamber 41b was 2.0 × 10 ⁻² [Pa]. Thereafter, the amount of oxygen introduced from the pinhole type nozzles 20 on the unwinding side and the winding side in the sheet conveyance direction of the evaporation source is gradually increased, and when it reaches 25 [l / min], the transmittance is 11 optical monitors. The average value of 52 showed 30%. In this state, the pressure in the film forming chamber 41b was 7.0 × 10 ⁻² [Pa]. In this state, 11000 [m] of film was wound and conveyed to form a film with an aluminum oxide film. Thereafter, the shutter member 51 was closed to stop the introduction of oxygen, and the power supply to the electron gun for heating the evaporation source was cut off. And the conveyance speed was lowered to 5 [m / min], and the pressure release of the winding chamber 41a and the film formation chamber 41b was performed.

The thickness of the aluminum oxide film thus formed was in the range of 70 ± 10 [nm] as a result of TEM cross-sectional observation. The total light transmittance of the deposited film taken out after the film formation was 59%. The surface resistance value was 3.9 × 10 ⁷ [Ω / □]. Table 1 summarizes the deposition conditions and evaluation results of the metal oxide thin film.

  The present invention is very suitable for vacuum vapor deposition for an electrically insulating plastic film, but can also be applied to vacuum vapor deposition of a web such as paper, and its application range is not limited thereto.

It is a schematic block diagram of the winding-type vacuum evaporation system which shows one embodiment of the manufacturing apparatus of this invention. It is a schematic block diagram of the winding-type vacuum evaporation system which shows one embodiment of the manufacturing apparatus of this invention. It is a schematic block diagram of the winding-type vacuum evaporation system which shows one embodiment of the manufacturing apparatus of this invention. It is a schematic block diagram of the winding-type vacuum evaporation system which shows one embodiment of the manufacturing apparatus of this invention. It is a cross-sectional schematic diagram of the one aspect | mode of the sheet | seat with a metal oxide thin film formed into a film by the conventional method. It is a cross-sectional schematic diagram of one aspect | mode of the sheet | seat with a metal oxide thin film formed into a film by the method of this invention. It is the schematic block diagram which showed an example of the conventional winding type vacuum evaporation system. It is the schematic block diagram which showed an example of the conventional oxygen supply means. It is the schematic block diagram which showed an example of the conventional winding type vacuum evaporation system used in the comparative example 1. It is the schematic block diagram which showed an example of the conventional winding type vacuum evaporation system used in the comparative example 2. 4 shows the composition analysis result in the thickness direction of the aluminum oxide film formed in Example 1. FIG. 3 is a composition analysis result in a thickness direction of the aluminum oxide film formed in Comparative Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet 2 Original roll body 3 Sheet guide surface 4 Intermediate roller (unwinding side)
5 Intermediate roller (winding side)
6 Winding roll body 7 Crucible (evaporation source)
DESCRIPTION OF SYMBOLS 8 Vapor deposition material 10 Vapor 11 Mask member 12 Opening part 13 Thin film 15 Introducing pipe 16 Introducing part of introducing pipe 17 Direction of introducing oxygen 18 Branching part 19 Oxygen supply pipe 20 Pinhole type nozzle 21 Pinhole 24 Bulkhead 25 Sheet conveying direction 26 Sheet deposition region 29 Gas introduction path 30 Deposition start point 31 Deposition end point 32 Separation point 33 Winding point 41 Decompression chamber 41a Winding chamber 41b Film forming chamber 42 Vacuum pump 42a Vacuum pump for winding chamber 42b Film forming Vacuum pump for room 43 Valve 44 Gas cylinder 45 Pressure reducing valve 46 Gas flow regulator 51 Shutter member 52 Optical monitor 53 Viewing window 61 Low metal oxide layer 62 High metal oxide layer

Claims (14)

A sheet guide surface configured to convey the sheet while being in contact with the sheet; a conveying unit configured to convey the sheet along with the movement of the sheet guide surface; and metal vapor is scattered toward the sheet on the sheet guide surface. An apparatus for producing a sheet with a metal oxide thin film, comprising: an evaporation source to be used; and an oxygen introduction means for introducing oxygen to cause an oxidation reaction with the metal vapor, wherein the metal oxide thin film is continuously formed on the conveyed sheet The oxygen introduction means is configured by arranging a plurality of introduction pipes at a predetermined interval in the sheet width direction, and the oxygen introduction means includes an upstream side in the sheet conveyance direction of the evaporation source and An apparatus for producing a sheet with a metal oxide thin film, wherein the sheet is disposed on the downstream side, and the introduction pipe projects toward a region between the evaporation source and the sheet guide surface. The shortest distance h between the evaporation source and the sheet guide surface is in the range of 200 to 800 [mm], and the opening of the introduction pipe is 0.2 × h [mm] or more from the evaporation source and 0 The apparatus for producing a sheet with a metal oxide thin film according to claim 1, wherein the apparatus is disposed at a distance of 8 × h [mm] or less. 3. The metal oxide according to claim 1, wherein the length of the introduction pipe is 30 [mm] or more and an inner cross-sectional area of the introduction pipe is in a range of 3 to 50 [mm ² ]. Manufacturing equipment for sheet with thin film. The metal oxide thin film forming apparatus according to claim 1, wherein an opening of the introduction pipe faces the sheet guide surface. The said oxygen introduction means has a mechanism which adjusts the distance from the said evaporation source of the said opening part, The manufacturing apparatus of the sheet | seat with a metal oxide thin film in any one of Claims 1-4 characterized by the above-mentioned. . The evaporation source is heated by an electron gun, and the evaporation source has a shape that is longer in the sheet width direction than the sheet conveyance direction, and further has a length in the sheet width direction of 300 mm or more. The manufacturing apparatus of the sheet | seat with a metal oxide thin film of Claim 5 characterized by the above-mentioned. Using the apparatus according to any one of claims 1 to 6, in a reduced pressure atmosphere, metal vapor is allowed to fly from the evaporation source toward the sheet, and at the same time, oxygen is introduced into the metal vapor, A method for producing a sheet with a metal oxide thin film that continuously forms a metal oxide thin film, wherein a plurality of introduction pipes provided in the width direction of the sheet on the upstream side and the downstream side of the evaporation source are made of metal. A method for producing a sheet with a metal oxide thin film, wherein oxygen is introduced into a region exposed to a vapor flow. A value obtained by dividing the amount of oxygen introduced from each introduction pipe of the oxygen introduction means by the inner cross-sectional area of the introduction pipe is in the range of 25 to 300 [× 10 ⁻⁶ m ³ / min / mm ² ]. It controls as follows, The manufacturing method of the sheet | seat with a metal oxide thin film of Claim 7 characterized by the above-mentioned. The method for producing a sheet with a metal oxide thin film according to claim 7 or 8, wherein the metal vapor is aluminum vapor, and an aluminum oxide film is formed on the sheet. The method for producing a sheet with a metal oxide thin film according to any one of claims 7 to 9, wherein a film formation rate of the metal oxide thin film is 400 [nm / sec] or more. The oxygen is introduced into a region where the metal vapor is scattered and a virtual film formation rate in the metal vapor is 1500 [nm / sec] or less. The manufacturing method of the sheet | seat with a metal oxide thin film in any one. The method for producing a sheet with a metal oxide thin film according to any one of claims 7 to 11, wherein the metal oxide thin film is formed so that a film thickness thereof is in a range of 50 to 300 [nm]. When the total light transmittance of the sheet with the metal oxide film is T [%] and the film thickness of the metal oxide thin film is d [μm], the value of the optical density represented by the following formula is 1.0 to 20. It forms into a film so that it may become in the range of 0, The manufacturing method of the sheet | seat with a metal oxide film in any one of Claims 7-12 characterized by the above-mentioned.
(Optical density) =-{log (T / 100)} / d A method for producing a sheet with a double-sided metal oxide film, wherein a metal oxide thin film is formed on both sides of an electrically insulating sheet by the method according to claim 7.

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